Quasiparticle Chirality in Epitaxial Graphene Probed at the Nanometer Scale

TL;DR

This study uses scanning tunneling microscopy to directly observe the pseudospin and electronic chirality of quasiparticles in epitaxial graphene, confirming theoretical predictions at the nanometer scale.

Contribution

It demonstrates a novel method to probe quasiparticle symmetry properties in graphene using STM and Fourier analysis, aligning experimental data with theoretical models.

Findings

Pseudospin and chirality in epitaxial graphene match ideal graphene predictions.

Quantum interference patterns reveal quasiparticle symmetry properties.

STM can effectively probe electronic symmetry at nanometer resolution.

Abstract

Graphene exhibits unconventional two-dimensional electronic properties resulting from the symmetry of its quasiparticles, which leads to the concepts of pseudospin and electronic chirality. Here we report that scanning tunneling microscopy can be used to probe these unique symmetry properties at the nanometer scale. They are reflected in the quantum interference pattern resulting from elastic scattering off impurities, and they can be directly read from its fast Fourier transform. Our data, complemented by theoretical calculations, demonstrate that the pseudospin and the electronic chirality in epitaxial graphene on SiC(0001) correspond to the ones predicted for ideal graphene.